1. Technical Field
This invention relates to antimicrobial dental care preparations.
2. Description of the Background Art
Oral compositions such as toothpastes, gels and mouth washes are designed to loosen and remove plaque in conjunction with a regular toothbrushing regimen, and typically include fluoride to prevent tooth decay. Dental plaque is present to some degree, in the form of a film, on virtually all dental surfaces. It is a byproduct of microbial growth, and comprises a dense microbial layer consisting of a mass of microorganisms embedded in a polysaccharide matrix. Plaque itself adheres thinly to dental surfaces and is removed only with difficulty even through a rigorous brushing regimen. Moreover, plaque rapidly reforms on the tooth surface after it is removed. Plaque may form on any part of the tooth surface, and is found particularly at the gingival margin, in cracks in the enamel, and on the surface of dental calculus. The danger associated with the formation of plaque on the teeth lies in the tendency of plaque to build up and eventually produce gingivitis, periodontitis and other types of periodontal disease, as well as dental caries and dental calculus.
Conventional treatments of plaque include antibacterial agents such as triclosan. Triclosan is known for inhibiting growths of microorganisms, especially bacteria. Because bacteria are components of plaque, triclosan may reduce plaque formation when it is effectively applied to the teeth. However, reports have suggested that triclosan has negative effects on humans and the environment.
Triclosan can be degraded by sunlight into a dioxin. Triclosan can also combine with chlorine in tap water to form chloroform gas, which the United States Environmental Protection Agency classifies as a probable human carcinogen. Experiments on Triclosan have demonstrated hazardous effects towards animals including liver, kidney and intestinal flora damage. Further, Triclosan accumulates in fatty tissue and passes into breast milk.
In certain toothpastes copolymers are added to increase the attachment to the gingiva. Thus the retention time of Triclosan in the oral cavity can be extended up to 12 hours. The retention time may add to the damage of the skin flora and may permanently damage the oral micro-flora.
Another disadvantage to Triclosan is the forming of a resistance. This occurs due to low concentrations and frequent use of Trisclosan. Cross resistance with frequently used antibiotics has also been observed and this may be a cause of antibiotic resistance.
Triclosan is also considered environmentally hazardous in water and is very difficult to degrade by biological means.
Taurolidine, taurultam, N-methylol taurinamide and the like are bactericidal compounds that do not exhibit the phenomenon of resistance due to their mechanism of action, which involves a cross-linking reaction with the cell wall of bacteria. Taurolidine is a synthetic derivative of the naturally occurring 2-aminoethane sulphonic acid, taurine. The use of taurolidine as a potential antimicrobial substance, acting by a methylol transfer mechanism, has been disclosed in GB 1,124,285. Taurolidine solution is sold by Ed. Geistlich Sohne AG. under the registered Trade Mark Taurolin®. The antibacterial substance taurultam is closely related to taurolidine and, indeed, is formed during the methylol transfer reaction between taurolidine and target substances. Taurultam is slightly more water soluble than taurolidine but possesses fewer methylol transfer groupings.
There continues to be a need for new formulations of an antimicrobial toothpaste.